Apparatus for tightening and locking a nut on a bolt

ABSTRACT

Apparatus for tightening a nut on a bolt comprising a body, a nut engaging wrench member rotatably and slidably mounted in the body, a pneumatic motor in the body to rotate the wrench member and a pneumatically operated vibratory impact device provided in the body and adapted to apply impacts to a deforming tool associated with the socket so that the deforming tool acts on the nut and displaces parts of the thread of the nut into locking engagement with the thread of the bolt.

United States Patent Turnbull 1451 July 4, 1972 I54] APPARATUS FOR TIGHTENING AND LOCKING A NUT ON A BOLT [72] Inventor: John Hilton Turnbull, Stourport on Severn, England [73] Assignee: G.K.N. Screws 8: Fasteners Limited, Warley, England [22] Filed: Aug. 12, 1970 [21] Appl. No.: 53,080

[52] US. Cl ..29/200 B, 29/240 51 1m. 01. ..B23p 19/00, B23d 19/04 I [58] Field of Search ..29/200 B, 200 R, 240, 200 J [56] References Cited UNITED STATES PATENTS 3,479,714 1l/1969 Allsop ..29/240 X Primary Examiner-Thomas H. Eager Auurney-Merriam, Marshall, Shapiro & Klose [5 7] ABSTRACT Apparatus for tightening a nut on a bolt comprising a body, a nut engaging wrench member rotatably and slidably mounted in the body, a pneumatic motor in the body to rotate the wrench member and a pneumatically operated vibratory impact device provided in the body and adapted to apply impacts to a deforming tool associated with the socket so that the deforming tool acts on the nut and displaces parts of the thread of the nut into locking engagement with the thread of the bolt.

6 Claims, 8 Drawing Figures PATENTEDJUH I972 SHEET 2 UF 2 4? SZ Vx/ APPARATUS FOR TIGIITENING AND LOCKING A NUT ON A BOLT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an improvement in and modification of the apparatus described and claimed in U.S. Pat. No. 3,479,714.

Such an apparatus is used for tightening and locking a nut on a bolt or other externally threaded stem and wherein, after being tightened on the bolt, the body of the nut or a portion thereon is deformed so as to cause a portion or portions on the internal thread of the nut to be displaced inwardly into locking engagement with the externally threaded stem so as toprovide increased resistance to any tendency for the nut to slacken off when in use, particularly in cases where the fastening is subject to vibration or other external forces when in use.

2. Description of the Prior Art In U.S. Pat. No. 3,479,7l4 there is described and claimed a tool for tightening and locking a nut upon a bolt having a nut engaging wrench member, power means for rotating said wrench member to apply torque to a nut engaged therewith, an impact member slidable in the tool in the axial direction of the wrench member, a deforming tool associated with the wrench member and positioned to engage the end face of the nut adjacent the free end of the bolt and power means for delivering an impact to said impact member to cause it to drive the deforming tool into engagement with said end face of the nut.

SUMMARY OF THE INVENTION An object of the invention is to provide an improved or modified tool for tightening and locking a nut upon a bolt or other threaded stem in which operation and control of the tool is simplified and an improved locking effect is obtained.

According to the invention, there is provided a tool for tightening and locking a nut upon a bolt comprising a body, a nut engaging wrench member, rotatably mounted in the body, power means for rotating the wrench member, to apply torque to a nut engaged therewith, an impact member slidable in the body in the axial direction of the wrench member, a deforming tool associated with the wrench member and positioned to engage the end face of the nut adjacent the free end of the bolt and a vibratory impacting device mounted in the body and I adapted, when operated, to deliver a rapid succession of impacts to the deforming tool in the direction axially of the wrench member to drive the deforming tool into deforming engagement with the end face of the nut.

To facilitate the operation of the tool a single control is preferable, and conveniently the power operated means for driving the torque transmitting member and also the vibratory impacting device are both pneumatically operated and under the control of a single main control valve, automatic means being provided to shut off the air supply to said power operated means when the nut has been tightened to a predetermined extent and simultaneously to open the air supply to the vibratory impacting device to bring this into operation.

The air supply to the vibratory impacting device may be additionally controlled by a valve which operates to cut off said air supply automatically after a pre-determined period of time.

BRIEF DESCRIPTION OF DRAWING There is hereinafter described by way of example an embodiment of the invention with reference to the accompanying drawing, wherein:

' FIG. 1 is a part-sectioned view in side elevation of one form of tool according to the invention,

FIG. 2 is a sectioned view showing the end of the tool on enlarged scale,

FIG. 3 is an end view looking from the right in FIG, 2,

FIG. 4 is a view of the end of the tool as in FIG. I with a nut engaged therein prior to application to a bolt,

FIG. 5 is a view showing the stage reached in tightening the nut prior to application of impact,

FIG. 6 is a view showing the stage subsequent to FIG. 5 when the impact has been delivered,

FIG. 7 is a plan view of the nut after the locking operation has been performed,

FIG. 8 is a section through the nut shown in FIG. 7.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIG. I, a tool embodying the invention comprises a main body portion 10, a first hand grip portion 1 I and a second hand grip portion 12, both said hand grip portions being generally tubular in configuration and extending from the main body portion 10 at an acute angle to the main central axis thereof.

A rearward extension 13 of the main body portion 10 houses a known form of pneumatically operated turbine I4, which, if desired, can be an impact turbine, and the output shaft of the turbine 14 drives a torsion bar 15 which transmits torque to a torque transmitting member, generally indicated at 16, through a coupling comprising an external sleeve 17 fixed at one end to the forward end of the torsion bar and at the other end having an axially extending passage 18 in which is slidably and non-rotatably engaged the rearward end 19 of the torque transmitting member I6. The end 19 of the torque transmitting member 16 has longitudinally extending splines engaging in axially extending slots in the passage 18 so that the torque transmitting member 16 is driven rotatably by the coupling sleeve 17, but the end 19 can slide relative to the sleeve 17 by virtue of the splined connection between the two.

The pneumatic turbine 14 and torsion bar 15 form part of a generally known construction of nut runner which also includes, in a pneumatic circuit supplying air to the turbine, a valve 20, generally referred to as the torsion valve, which operates to automatically cut off the supply of air to the turbine when the torsion bar 15 is torsionally deflected through a pre-determined angle corresponding to a pre-deterrnined torque resistance so that the extent to which a nut is tightened by the torque transmitting member 16 can be pre-determined and once such torque resistance is encountered the valve 20 will operate automatically to cut off the supply of air to the turbine.

In the second hand grip portion 12 there is housed a known form of vibratory impacting device which comprises a vibrating motor 22 which drives a reciprocating impact piston 23 and when operated causes a rapid reciprocation on the impacting piston 23 whereby the piston 23 delivers a rapid series of impacts to an impact member disposed at the outer end of its stroke.

The impacts from the impact piston 23 are transmitted to the torque transmitting member 16 via a striker member, generally indicated at 24, housed in the forward end of the main body portion 10 of the tool, the striker member being generally of two-armed form and having one am 25 disposed so that it is engaged by the impact piston 23 at the end of its stroke. The striker member 24 is pivotally mounted about a transverse axis 26 and its other arm 27 is of bifurcated form and engages against a radially extending flange 28 which is formed intermediate the ends of the torque transmitting member 16. With this arrangement, impacts applied to the arm 25 of the striker member are transmitted to the torque transmitting member as axially directed impacts in the axial direction of the torque transmitting member and thus in the axial direction of the nut-engaging wrench member which will be mounted on the adapter end 21 of the torque transmitting member.

Compressed air for the operation of the turbine 14 and vibrating motor 22 is admitted to the tool through an inlet opening 29 in the lower end of the first hand grip portion 11, there being provided a suitable adapter 30 for connecting to a supply of compressed air; and air which is admitted passes into the hollow interior 3] of the first hand grip portion 11 and is admitted to the turbine 14 via a main control valve, generally indicated at 32. The trigger 33 of the control valve operates directly upon a waisted piston 34 which is normally urged by a spring 35 into the closed position as shown in the drawings, and when the trigger 33 is depressed air is admitted via passage 36 tothe turbine 14 via the torsion valve 20.

The lower ends of the first and second hand grip portions 11 and 12 are connected by a bridge piece 37 in which are, housed a time control valve 38, of known construction, and a relay 38', also of known construction. A passage 40 is provided in the body of the gun extending from the torsion valve 20 downwardly through the first hand grip portion 11 and through the bridge piece 36 to communicate with the relay 39. A further passage 41 admits air from the chamber 31 to the time controlvalve 38and then to the relay 39.

The torsion valve 20 is constructed so that when it operates in the normal way to cut off the supply of air to the turbine 14 it also sends a signal via the passage 40 to the relay 39 which functions to startthe operation of the time control valve 38 and admit air under pressure to the vibrating motor 22.

Referring now to FIG. 2, the forward end of the torque transmitting member 16 is in the form of an adapter 21 of square or other non-circular cross section; and this is adapted to have, non rotatably fitted thereto, a nut-engaging wrench member 42 which is illustrated in FIGS. 2 to 6 and is constructed sothat it has a nut engaging socket portion43 to engage a nut 44, see FIGS. 4 to 8, for applying tightening torque thereto and also embodies a deforming tool 45 having three forwardly projecting portions 46 equiangularly spaced around the periphery. of an axial passage 49 in the tool. The passage 49 communicates axially with a passage 50 in the part 21 and the forward end of the part 21 abuts against an internal shoulder 51 in the wrench member 42 whereby axial impact from the impact piston 23 is transmitted to the deforming tool 45. Thus, when the vibratory impacting motor is operated, the portions 46 are driven forwardly so as to engage the end face 47 of the nut 44 around the threaded opening therein and displace portions of the nut face 47 and the immediately adjacent internal thread into locking engagement with the thread of a bolt 48 to which the nut has been applied.

The tool is operated in the following manner. Referring now to FIGS. 4, and 6, these show three stages in the application of a nut 44' to the threaded end of a bolt 48 for holding together two members 52 and 53 in a nut and bolt assembly, and in this particular example the assembly has a washer 54 placed on the bolt so as to be underneath the nut when the nut is applied to the bolt.

FIG. 4 shows the nut 44 engaged in the socket 43 of the wrench member 42 prior to application of the bolt.

The trigger 33 is depressed to admit compressed air to the turbine 14 and start the torque transmitting member 16 to rotate so that it rotates the wrench member and runs the nut 44 onto the end of the bolt 48 in the normal way until the stage shown in FIG. 5 is reached and the nut 44 is run into engagement with the washer 54 thereby increasing the torque resistance encountered by the tool until the torque reaches a pre-determined value whereupon the torsion valve 20 is caused to operate in known manner to cut off the supply of air to the turbine 14 and thus cease application of torque to the nut 44.

Simultaneously with the cutting off of the supply of air to the turbine 14 an air signal is passed by the torsion valve 20 via passage 40 to the relay 39 which functions to admit air to the vibrating motor 22 via passage 41.and time control valve 38 so that the vibrating motor 22 is caused to operate and a rapid series of impacts are delivered by the impact piston 23 to the striker member 24 thus delivering impact axially via the torque transmitting member 16, adapter 21 and shoulder 51 of the wrench member 42 to the deforming tool 45 so that this advances relative to the nut 44 and the three projections 46 form indentations in the end face 47 of the nut (see FIG. 6) as explained in more detail hereinafter with reference to FIGS. 7 and 8.

As the effect of the. impacting causes the wrench member 42 and deforming tool 45 to move (in the direction from left to right in FIG. 6) relative to the nut 44, the end face 55 of the wrench member 42 impacts against the washer 54, and the presence of the washer 54 avoids any indentation being caused on the outer surface of the member 52.

To provide for this movement axially of the wrench member 42, the socket 43 is of such axial depth that when the nut is engaged therein (see FIGS.,4 and 5), the one end face of the nut projects slightly beyond the end face 55 of the wrench member 42.

Referring now to FIGS. 7 and 8 the impact of the three projections 46 of the deforming tool produces three corresponding indentations 56 in the end face of the nut 44, and as seen in FIG. 8, these indentations deform the thread of the nut at localized positions immediately adjacent this one end face of the nut so as to force these portions of the thread radially inwardly into firm frictional engagement with the thread of the bolt so as to achieve the desired locking action.

The invention thus provides an extremely compact tool which, in a practical embodiment, is no more bulky than a normal form of nut runner; and this is achieved because of the particular arrangement of the vibrating motor and impact piston of the vibratory device being housed in the tubular second hand grip portion and with the remaining controls, such as the time control valve and relay and main control trigger being housed in the other handgrip portion of the complete body of the tool. Further, the arrangement of single control and the automatic operation of the torsion valve 20 enablesan operator to tighten a nut on a bolt and lock it in position with a single operation of the tool.

lclaim:

1. A tool for tightening and looking a nut upon a bolt comprising a body, a nut engaging wrench member, rotatably mounted in the body, power means for rotating the wrench member, to apply torque to a nut engaged therewith, an impact member slidable in the body in the axial direction of the wrench member, and a deforming tool associated with the wrench member and positioned to engage the end face of the nut adjacent the free end of the bolt, wherein the improvement comprises a vibratory impacting device mounted in the body and adapted, when operated, to deliver a rapid succession of impacts to the deforming tool in the direction axially of the wrench member to drive the defonning tool into deforming engagement with the end face of the nut.

2. A tool according to claim 1 wherein the power means for rotating the wrench member and the vibratory impacting device are both pneumatically operated and there being a single main control valve member and automatic means to interupt supply of air to the power operated means when the nut has been tightened to a pre-determined extent and then to open the air supply to the vibratory impacting device.

3. A tool according to claim 2 wherein the air supply to the vibratory impacting device is also controlled by a valve which can operate to interupt said air supply to the vibratory impacting device automatically after a pre-determined time of impacting.

4. A tool according to claim 1 wherein the vibratory impacting device is operable to drive an impact piston in a direction inclined to the axial direction of the wrench member and the impact piston being adapted to engage one arm of a two armed striker member mounted for pivotal movement about an axis transverse and spaced from said axial direction of the wrench member, the other arm of the two armed striker member being adapted to engage a member to move a member in the axial direction of the wrench member to transmit the impacts from the piston to the deforming member.

5. A tool according to claim 4 wherein the tool is in the form of a gun having an elongated main body portion extending in the axial direction of the wrench member and having two hand grip portions depending therefrom in spaced generally parallel relationship, the hand grip portion closest to the wrench member housing the vibratory impacting device and the other turbine.

i l i 

1. A tool for tightening and locking a nut upon a bolt comprising a body, a nut engaging wrench member, rotatably mounted in the body, power means for rotating the wrench member, to apply torque to a nut engaged therewith, an impact member slidable in the body in the axial direction of the wrench member, and a deforming tool associated with the wrench member and positioned to engage the end face of the nut adjacent the free end of the bolt, wherein the improvement comprises a vibratory impacting device mounted in the body and adapted, when operated, to deliver a rapid succession of impacts to the deforming tool in the direction axially of the wrench member to drive the deforming tool into deforming engagement with the end face of the nut.
 2. A tool according to claim 1 wherein the power means for rotating the wrench member and the vibratory impacting device are both pneumatically operated and there being a single main control valve member and automatic means to interupt supply of air to the power operated means when the nut has been tightened to a pre-determined extent and then to open the air supply to the vibratory impacting device.
 3. A tool according to claim 2 wherein the air supply to the vibratory impacting device is also controlled by a valve which can operate to interupt said air supply tO the vibratory impacting device automatically after a pre-determined time of impacting.
 4. A tool according to claim 1 wherein the vibratory impacting device is operable to drive an impact piston in a direction inclined to the axial direction of the wrench member and the impact piston being adapted to engage one arm of a two armed striker member mounted for pivotal movement about an axis transverse and spaced from said axial direction of the wrench member, the other arm of the two armed striker member being adapted to engage a member to move a member in the axial direction of the wrench member to transmit the impacts from the piston to the deforming member.
 5. A tool according to claim 4 wherein the tool is in the form of a gun having an elongated main body portion extending in the axial direction of the wrench member and having two hand grip portions depending therefrom in spaced generally parallel relationship, the hand grip portion closest to the wrench member housing the vibratory impacting device and the other hand grip portion housing the main control valve.
 6. A tool according to claim 1 wherein the power means for rotating the wrench member comprises a pneumatic impact turbine. 